Question: Solve for $x$ and $y$ using substitution. ${-5x+6y = 1}$ ${x = 5y-4}$
Explanation: Since $x$ has already been solved for, substitute $5y-4$ for $x$ in the first equation. ${-5}{(5y-4)}{+ 6y = 1}$ Simplify and solve for $y$ $-25y+20 + 6y = 1$ $-19y+20 = 1$ $-19y+20{-20} = 1{-20}$ $-19y = -19$ $\dfrac{-19y}{{-19}} = \dfrac{-19}{{-19}}$ ${y = 1}$ Now that you know ${y = 1}$ , plug it back into $\thinspace {x = 5y-4}\thinspace$ to find $x$ ${x = 5}{(1)}{ - 4}$ $x = 5 - 4$ ${x = 1}$ You can also plug ${y = 1}$ into $\thinspace {-5x+6y = 1}\thinspace$ and get the same answer for $x$ : ${-5x + 6}{(1)}{= 1}$ ${x = 1}$